Okay, so why is the Federal government preventing vacuum barges from sucking crude oil out of the sea in the Gulf? I've heard many conspiracy theories...
"You never want a serious crisis to go to waste." Claiming they're exacerbating the spill to forward political ends doesn't fit; no matter how many barges they deploy, they'll never get more than a fraction of the oil that's been let loose in the ocean; their efforts simply wouldn't reduce the pollution enough to matter. No sense wasting effort and spawning a media frenzy over blocking the barges.
"They're hiding something that's in the oil!" Unlikely. Even with all the military materiel that was dumped in the area of the well, anything that would've ruptured near the site would've been heavily diluted. Even a large amount of VX would become overly dilute.
"They're hiding the size of the spill!" I don't see how the barges would make a difference.
My guess? They're trying to keep the oil from being salvaged. Large amounts of oil recovered from the ocean would be sold and refined into useful products, increasing the petroleum supply and driving down prices. A bit of cash thrown at the Obama administration to keep this oil off the market would pay off in keeping the cash rolling in for the oil companies.